The present invention relates to collapsible canopy structures and frameworks for such structures.
Building assemblies are known that have a foldable capability so that they may be erected where desired and, when necessary, folded up to a compact form for storage and/or transportation. These assemblies employ column-like elements or rods as basic construction units that function as stays. The links are interconnected with pivot joints, slip joints, or other forms of movable interconnects so that a collapsible, articulated structure is formed. A fabric covering is usually associated with the network of rods. An example of such a collapsible structure is shown in U.S. Pat. No. 3,185,164, which shows a structure including a plurality of rods joined by couplings into groups of three which are inter-related to form a generally hexagonal structural system. Another example of such a collapsible structure is shown in U.S. Pat. No. 3,710,806. Structures that utilize elements intended to maintain the rigidity of the structure are also known, as exemplified in U.S. Pat. No. 3,063,521.
Collapsible frame structures for supporting tents or other outdoor shelters are also known. Examples of collapsible frames for use in supporting such tents or outdoor structures are shown in U.S. Pat. Nos. 563,376; 927,738; 1,773,847; and No. 2,781,766. Such structures have varied widely in their ease of erection and storage, and are of varying structural strength.
Collapsible structures are described in my prior U.S. Pat. Nos. 3,968,808; 4,026,313; 4,290,244; 4,437,275; 4,473,986; 4,512,097; 4,522,008; 4,561,618; 4,579,066; 4,689,932; 4,761,929; and No. 4,838,003. In these patents, the structural frameworks include scissor assemblies are comprised of pivotally connected members of fixed length. My U.S. Pat. No. 3,968,808 discloses a self-supporting domed shelter constructed from a series of intermeshing pentagonal or hexagonal sections, each section being composed of crossed pairs of pivotally connected struts. The generally semi-spherical framework is made of elongate struts and hub means which are movable between a collapsed, bundled condition (in which the struts are closely bundled and in a generally parallel relationship) and an expanded condition or three-dimensional form. This structural framework is self-supporting by virtue of self-locking action resulting from the asymmetrical disposition of certain struts. The framework has zones of sliding connections between crossed struts that allows the structure to be collapsed. My U.S. Pat. No. 4,026,313 discloses sliding and pivoted connections and rectangular modules, among other things, and my U.S. Pat. Nos. 4,290,244 and 4,437,275 generally are directed to structural modules.
My U.S. Pat. No. 4,689,932 discloses an octahedral module that provides the ability to build long, narrow structures or tall, wide structures. With this octahedron-based design, the struts that define the structural modules may be of equal length. The octahedron-based design also introduced a 90-45 degree coordinate system that permits "stretchability" on three axes because each of the modules has the same edge lengths. That is, the controlled addition of modules permits the basic octahedron to be dimensionally increased in three mutually orthogonal directions: height, width, and length. My patent discloses a dome structure composed of two types of square modules: a "flat" module; and a "transition", or cylindrical, module. The circumscribing sides of all the modules are formed by crossed, pivotally connected struts. With this design, the resulting building has a generally spherical shape that is substantially horizontal at the top of the structure and substantially vertical near the bottom of the structure, there being a curved portion therebetween formed by the transition modules. With this design, the corner portions of the building are left open if, for example, passageways are desired, as shown in FIGS. 1-3 of the patent. As the size of the structure increases, the open corner sections become larger.
Many typical prior building designs, including geodesic domes and conventional structures such as frame tents, suffer from several general problems. If the structure is collapsible, it is often difficult to erect and requires several workers, a significant amount of time, and special tools and equipment. The structures are also often complex in construction, having several different detachable parts and being relatively heavy and bulky in size. Non-uniformity of the sizes of the structural members also contributes to the overall complexity and cost of such structures. Many conventional structures, such as frame tents having flat roofs, are limited in their aesthetic appeal. As a result, the appropriate uses of these structures are limited.
Fabrication of some collapsible structures, such as canopies having horizontal dimensions less than about twenty feet in length, presents special concerns because access to the limited interior space should not be excessively restricted by placement of the structural members. For example, the height of the canopy, which is typically determined by the lengths of posts, or legs, disposed at its corners, usually also determines the lengths of the crossed struts, or scissor members, that form the framework supporting the roof of the structure. To obtain the desired width and height with appropriate structural stability, the scissor members may be splayed to such an extent that access to the area under the canopy is restricted.
Telescoping or otherwise changeable elements in rod frameworks are described in U.S. Pat. No. 3,940,892 to Lindbergh; No. 3,973,370 to McAllister; No. 4,641,477 to Schleck; No. 4,655,022 to Natori; and Nos. 4,888,895 and 4,942,686 to Kemeny. The Lindbergh patent describes the erection of an aircraft enclosure by forming an arch through the extension of a piston in a hydraulic cylinder. The McAllister patent discloses the erection of a structure comprising a framework having extendable struts. Schleck teaches a modular rod/truss structure having chord and diagonal members comprising turnbuckles for length adjustments that permit arch construction. Natori teaches a framework including extendable truss beams that permit fabrication of a curved structure. The Kemeny patents teach a scissors-type framework in which telescoping members permit different curvatures to be developed.
U.S. Pat. No. 4,607,656 to Carter and Nos. 4,641,676 and 4,779,635 to Lynch describe relatively small collapsible canopy structures. In each of these patents, the canopy structure comprises a flexible covering and a framework that includes a number of telescoping legs and scissor assemblies, or X-shaped linkages, between the legs. The fixed arm lengths and single pivots of the scissor assemblies significantly constrain the dimensions, i.e., the distances between the ends of the arms, achievable with such scissor assemblies because an increase in one of those distances can only be achieved by either lengthening the arms, which may make the collapsed framework unwieldy, or increasing the angle between the arms, which may restrict access to the structure.
The present invention addresses these and other problems associated with known collapsible support structures. Among its several features and advantages, the present invention provides collapsible canopy structures that have relatively small horizontal dimensions and unrestricted interior access. These features and advantages are provided by including in the framework several scissor assemblies having telescoping members, as well as the "ring and blade" hubs and locking devices described in my above-cited U.S. patents and the parent of the present application.